This invention relates to the enabling of broadband data transfer between a Public Service Network and customer premise equipment.
Various types of modems are conventionally used in transferring data to and from customer premise equipment via the telephone system. Conventional POTS (Plain Old Telephone System) modems have long been used, and in a typical application the customer premise includes a POTS modem and the central office includes a pool of POTS modems. More recently, digital modems such as xDSL, ISDN, and other digital modems have come into widespread use due to their inherent ability to support higher speeds. As before, when digital modems are used a digital modem is provided at the customer premise, and a bank of digital modems is provided, usually at the central office. This bank of digital modems is often referred to as a DSLAM (Digital Subscriber Line Access Multiplex). The DSLAM is further connected to a metropolitan network, enabling xe2x80x9calways onxe2x80x9d connections to Internet service providers (ISP""s) and the Internet.
The path length between two modems principally determines the maximum rate at which information can be exchanged between them. The end points of this path are usually the customer or user""s premise (home) and the central office. A distance of 12,000 feet can support a 1.5 mbit/sec ADSL link, while a distance of 2000 feet can support a 6 mbit/sec VDSL link. Too often the wire path distance exceeds the practical limit of Digital Subscriber Line (DSL) modems, which for the lowest-rate xDSL service (IDSL) is approximately 20,000 feet. However, analog POTS modems, such those implementing the V.92 standard, can carry data at a rate of up to 56 Kbps over the same path. Greater distances will reduce the maximum data transfer rate, for example to 26 Kbps.
The public telephone network architecture was originally designed to meet the requirements for conveying voice signals over dedicated lines. A line path consists of spliced or contiguous twisted pairs of copper wire. Although the wire pairs may originate together in a bundle (or trunk) at the same location such as the central office, they terminate at different lengths, as each user premise is usually located at a unique distance from the central office. While the longest path may just meet voice requirements, shorter paths have greater data rate potential that, up until the advent of DSL, went untapped.
At the present time, approximately 50% of all homes connected to a typical central office cannot be serviced by DSL due to the fact that (a) the home is served by a Digital Loop Carrier (DLC), or (b) the cable distance between the serving Central Office and the home exceeds the distance required for xDSL services. One solution is to wait until a future date when either multiple mid-span repeaters or amplifiers are installed along the telephone wire path from the central office to the customer or user""s premise, or until remote DSLAM""s are installed closer to the more distant user""s home or premise. Both these solutions fall short for a number of technical and logistical reasons.
Potentially, mid-span repeaters or amplifiers can be installed at several points along the path of the telephone cable. Unless there are simple plug/socket connections at the end points of wire bundle segments, and the segments are already conveniently located at suitable points along the path, each mid-span unit will require splicing of wire bundles or careful assignment of individual wires matching the mapping of wires in the original junction box that the mid-span amplifier unit replaces.
A remote DSLAM such as the Copper Mountain CopperEdge 200 RT DSL Concentrator requires a large cabinet, a power source, and a T-1 or fiber optic digital link from the cabinet to the central office. A T-1 link over a traditional four-wire pair to the central office may not provide an adequately high data rate, and therefore mid-span repeaters may be needed in addition to the remote DSLAM installation itself. The remote DSLAM is usually only economical for dense clusters of potential users, and is not well suited for the sparse and scattered distribution pattern of suburban or rural homes.
Thus, a need presently exists for improved systems for the enabling and transport of new broadband data services to and from customer premise equipment at high data rates.
By way of introduction, the systems described below transfer data via a multiplexer which is installed between a network interface (such as a central office) and customer premise equipment. The multiplexer functions as a remote access node, and it is coupled with the network interface either directly or indirectly via a set of upstream data links and with the customer premise equipment by a set of downstream data links. This multiplexer automatically, dynamically, and adaptively routes data between an appropriate number of the upstream data links and each downstream data link, in accordance with currently-prevailing data-rate requirements.
In one application, when any one of the customer premise equipment requests a first, lower-data-rate class of service (e.g. by issuing a http service request), the multiplexer transfers data between the associated downstream data link serving the customer and a single one of the upstream data links. Additionally, when any of the customer premise equipment requests a second, higher-data-rate class of service (e.g. by issuing a FTP service request), the multiplexer transfers data between the associated downstream data link and two, or more upstream data links. By allocating an appropriate number of the upstream data links to each downstream data link in accordance with the data-rate requirements of the downstream data link, the data-carrying capacity of the upstream data links is used efficiently, and improved levels of service can be provided,to the customer premise equipment using the currently-installed data links.
In another application, one or more DSL modems included in the multiplexer are dynamically time-shared among a larger number of subscribers. In this way, DSL service is provided in a particularly cost-efficient manner to every subscriber served by the multiplexer.
The foregoing paragraphs have been provided by way of general introduction, and they should not be used to narrow the scope of the following claims.